A Vehicle-Mounted Communication System includes a two-way mobile (vehicular) radio installed in a vehicle in either a dash mount or remote mount configuration. A dash-mounted radio system typically comprises a console or control head and a transceiver mounted under the dashboard of a vehicle, whereas a remote-mounted radio system may have various radio components situated in other parts of the vehicle, such as the transceiver in the trunk. The Vehicle-Mounted Communication System often includes a front microphone, also called a “potato mic” or a handheld microphone, attached to the control head and may optionally have a rear microphone attached to an accessory port, such as a rear accessory connector. The front microphone typically utilizes a push-to-talk (PTT) switch, while the rear microphone is typically provided with PTT capability via a footswitch.
Audio routing in the vehicular radio traditionally follows a set of rules, referred to as “microphone follows PTT” rules. According to these rules, when the PTT button associated with a given microphone is pressed, then the vehicular radio transmits the audio received at the associated microphone. For example, when the PTT button associated with the rear microphone is pressed, then transmission audio is taken from the rear microphone. The audio paths are distinct and individually controllable and the PTTs are individually detectable. Historically, Vehicle-Mounted Communication Systems, for example systems developed by Motorola, Inc. have followed the convention of “microphone follows PTT” for radio operation.
The vehicular radio also includes an audio power amplifier (PA) which drives a main speaker and, subsequently, conveys received audio to a user. In a Vehicle-Mounted Communication System, the main speaker can be integrated into the control head, or it can be a remote, external speaker connected to an accessory port.
Additionally, the vehicular radio may be optionally configured for a public address mode of operation. If the radio is so configured, an auxiliary speaker, typically containing an integral audio power amplifier, is installed and attached to a designated port on the radio's rear accessory connector. This auxiliary speaker is not the same as the external speaker previously mentioned. While both speakers are “external” to the radio, the external speaker is typically an un-powered speaker used as a main radio speaker and driven by the radio's built-in audio PA. In contrast, the auxiliary speaker is typically a powered speaker that operates independently from the external speaker. Alternatively, the vehicular radio can be designed such that either of the speakers, external and auxiliary, can be powered or un-powered.
Additionally, a “Public Address Switch” can be mounted on the vehicular radio or mounted external to the vehicular radio and wired to the accessory connector. The Public Address switch is used to enable or disable a public address mode of operation. If the Public Address switch is off, then the radio operation is “normal” meaning that the audio received by the vehicular radio goes to the main speaker powered by the radio's internal audio power amplifier and the audio that is to be transmitted by the vehicular radio, using radio frequency (RF) transmission, goes from a front or rear microphone to the transmitter (with the PTT button determining the particular microphone audio source). If the Public Address switch is on, then RF transmission of the audio by the handheld microphone is disabled. In this case, pressing the PTT button associated with the handheld microphone routes audio from the handheld microphone to the auxiliary speaker. Note that it is possible (by design) for a user to use public address while the radio is receiving audio and conveying the received audio over the main speaker. The public address feature is commonly used on buses and other public transportation.
Optimizing the routing of audio in a vehicular environment in accordance with the variety of different operating modes can be challenging. The user may be operating the radio system within a variety of different scenarios. For example, police officers may utilize the vehicular radio while driving or while standing outside of the vehicle and need to switch from using one microphone or speaker to another. Implementing accessories to operate as part of the communication system within the vehicular environment presents many design challenges, including size, cost and ease of operation. While certain accessories may provide desired functionality in a cellular environment, many such devices are not readily applicable to the two-way radio environment, largely due to the PTT nature of the two-way system. A common off the shelf (COTS) Bluetooth headset, for example, traditionally used with a cell phone is not very useful with vehicular radios as two-way radios generally require a PTT button. The use of headsets in general can be problematic in a vehicular environment. For example, if the headset falls off while the user is driving, communication is disrupted.
Accordingly, it would be desirable to have an improved communication system, particularly for the vehicular environment.
Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of embodiments of the present invention.